I. Field of the Invention
This invention relates to stands used with warning lines to provide fall protection.
II. Fall Protection
Safety Engineers have found that falls are the most frequent cause of deaths in the construction industry. In the United States of America, the Occupational Safety and Health Administration (OSHA) has set specifications of a number of acceptable methods of fall protection for various situations.
Warning line systems provide acceptable fall protection for work performed on flat rooftops. A warning line system consists of a rope and stands which fence off the perimeter of a work area. The rope (called a warning line) is fastened from stand to stand. When a worker moves out of the work area, he contacts the warning line and is alerted to the fall danger.
OSHA specifications for warning line systems require that stands have a quantity of resistance to being knocked over, and that the warning lines hang neither too high or too low to effectively warn a worker.
III. Commercial Use
Commercial use of fall protection has been subject to business economics. While fall protection has reduced accidents and the high cost of injuries, its use has also increased the cost of construction by requiring the cost of additional equipment, labor to set up and use the protection, reduced efficiency due to the restriction of movement, the burden of working around the protection, and the cost of removing it. The net result has been increased cost which is passed on to the consumer.
Construction companies have sought to reduce the costs by choosing protection systems that are inexpensive, easy to use, and improve their workers' productivity. In flat rooftop construction, warning line systems have been popular because of their portability, and flexibility to a variety of roof geometries. Construction companies have found that warning line systems that use light, compact, one-piece, quickly set up stands allow the cheapest cost of fall protection. Stands that lie out of the work area increase the speed of work and decrease costs.
IV. Description of Prior Art
An early stand consisted of a concrete filled tire with an embedded steel post. They often weighed over 90 pounds, were awkward to lift and difficult to transport to the job site because they were large and could not be stacked efficiently.
Another stand consisted of a steel base plate with a stud welded to its center onto which a length of pipe could be could be inserted. Although more compact than concrete filled tires, the base plate stands still weighed 50 pounds, were awkward to lift, and stacked poorly in a heavy, menacing pile.
Another stand consisted of a base of two long bars that formed an X upon which a post was pinned. It folded by removing the pin, pivoting the base bars together, setting the post lengthwise onto the bars, and repinning the parts together into an approximately rectangular package that made stacking more compact than other stands. Although the stands were approximately rectangular, they included a protruding handle that made stacking more than one high difficult, and they required several manipulations to setup and take down.
All previous art has used a post set vertically in the center of a base. Consequently, when the warning line is strung from stand to stand it sets above the center of each base, making part of the base of each stand lie within the work area. When working near the perimeter of the work area, the bases of the stands are in the way and roof workers often untie the stands and move them out of the way to complete their work. The presence of the bases in the work area interrupts work and reduces efficiency. Other drawbacks include the need for field assembly.